Safety clamp for walking beam compressor

ABSTRACT

Various methods and devices are provided for securing a walking beam compressor to a walking beam. In general, the walking beam compressor is a gas compressor unit that can be disposed around a piston rod extending from a walking beam of an oil well. The piston rod can be coupled to the walking beam by a securing mechanism that engages both the piston rod and the walking beam to prevent the piston rod from disengaging from the walking beam during rocking movement of the walking beam.

FIELD OF THE INVENTION

The present invention relates to gas compressors to be used with oilwells, and in particular to methods and devices for securing a walkingbeam compressor to a walking beam.

BACKGROUND OF THE INVENTION

A common oil well pumping system includes a walking beam mounted upon ahorizontally-axised, transverse pivot at the top of a Samson post. Oneend of the walking beam is connected to a pump rod and the other end isconnected to the crank of a drive motor through a connecting rod.Rotation of the crank causes the walking beam to rock or oscillate in avertical plane to raise and lower the pump rod. The rod-connected end ofthe walking beam is provided with the familiar “horse head” to keep thepump rod in alignment with the well axis. The opposite end of thewalking beam carries a counterbalance weight to offset the weight of thepump rod and minimize the stress on the motor.

When pumping an oil well, both oil and gas may be produced and thecapture of the gas is both profitable and better for the environment.Thus, an oil well pumping system can include a compressor unit mountedbetween the walking beam and a stationary part of the pumping unit forcompressing the natural gas produced during the pumping of the oil. Sucha compressor unit is called a walking beam compressor because it has apiston rod that is coupled to the walking beam. Rocking of the walkingbeam reciprocates the piston rod to effect intake and compressionstrokes. Over time, due to the reciprocating motion, the connectionbetween the piston rod and the walking beam can weaken or break. Thiscan cause two problems. First, as the piston rod loosens, the piston rodstroke length within the compressor changes. The additional strokelength can cause the piston to bottom out against the bottom of thecompressor, damaging both the compressor and the piston assembly.Second, the piston rod will eventually become completely detached fromthe walking beam. This may cause the compressor and piston rod to fallaway from the walking beam, resulting in costly damage and possibly adangerous situation.

Accordingly, there is a need for methods and devices that caneffectively secure a piston rod to a walking beam of an oil well pump.

SUMMARY OF THE INVENTION

The present invention generally provides a safety clamp for use with awalking beam compressor. In one embodiment, an oil well pump is providedand includes a walking beam for pumping oil out of the ground. A housingcan be mated to the walking beam and can have a piston rod extendingtherefrom configured for reciprocal longitudinal movement in response torocking movement of the walking beam. A safety clamp can be coupled tothe housing and the piston rod and it can be configured to prevent thepiston rod from rotating relative to the housing. While the piston rodcan be mated to the housing in various ways, in one embodiment thepiston rod can be threadably mated to the housing. For example, thehousing can include a threaded bore to receive a threaded terminal endof the piston rod. In one exemplary embodiment, the housing can be aclevis eye. The walking beam can have a beam plate coupled thereto andthe housing can be rotatably mated to a bracket extending from the beamplate.

The safety clamp can have a variety of configurations, but in generalthe safety clamp can be configured to prevent the piston rod fromrotating relative to the housing. In one embodiment, the safety clampcan include first and second legs that can engage opposing recesses inthe piston rod. The safety clamp can further include a central armextending from between the first and second legs that can be coupled tothe housing such that the safety clamp is substantially L-shaped. Thesafety clamp can also include a retaining element extending between thefirst and second clamping legs and configured to secure the clampinglegs to the piston rod.

In another exemplary embodiment, an oil well pump is provided having awalking beam for pumping oil out of the ground. A housing, for example aclevis eye, can be rotatably coupled to the walking beam and can have athreaded bore formed therein. A piston rod having a first threadedterminal end can be threadably mated to the threaded bore in the housingand can have a second terminal end extending into a compressorconfigured to receive and compress gas contained with oil pumped out ofthe ground. The oil well pump can further include a safety clamp coupledto the housing and the piston rod and configured to prevent the pistonrod from unthreading from the housing.

In one embodiment, the safety clamp can include first and secondclamping legs positioned in opposing recesses in the piston rod. Thesafety clamp can further include a central arm extending from betweenthe first and second clamping legs and coupled to the housing. Theclamping legs and central arm can be configured to prevent the pistonrod from rotating. In one embodiment, the central arm extendssubstantially perpendicular to the first and second clamping legs toform a substantially L-shaped safety clamp. The safety clamp can furtherinclude a retaining element extending between the first and secondclamping legs and configured to secure the clamping legs to the pistonrod.

In other aspects, methods of securing a piston rod to a walking beam onan oil well pump are provided. In one embodiment, the method can includethreading a piston rod into a housing coupled to a walking beam forpumping oil out of the ground, and coupling a safety clamp to thehousing and the piston rod to prevent the piston rod from unthreadingfrom the housing. In one embodiment, coupling the safety clamp to thehousing can include bolting a central arm of the safety clamp to thehousing. Further, coupling the safety clamp to the piston rod caninclude positioning first and second clamping legs of the safety clampwithin opposing recesses formed in the piston rod. A retaining elementcan be bolted to the first and second clamping legs to prevent removalof the first and second clamping legs from the piston rod.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a side-view of one embodiment of an oil well pump having acompressor coupled to a walking beam by a securing mechanism having asafety clamp;

FIG. 2 is a perspective view of the securing mechanism of FIG. 1;

FIG. 3 is a perspective view of the safety clamp of FIG. 1 coupled to apiston rod and a housing;

FIG. 4A is a perspective view of the safety clamp of FIG. 1;

FIG. 4B is a top view of the safety clamp of FIG. 1;

FIG. 4C is a head-on view of the safety clamp of FIG. 1; and

FIG. 4D is a side view of the safety clamp of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

The present invention generally provides a safety clamp for use with awalking beam compressor and methods for assembling and using the same.In general, a walking beam compressor is a gas compressor unit that canbe disposed around a piston rod extending from a walking beam of an oilwell or oil rig. The piston rod can be coupled to the walking beam by asecuring mechanism mated therebetween. While the securing mechanism canhave various configurations, in an exemplary embodiment the securingmechanism includes a safety clamp that can couple to both the piston rodand a housing mated to the walking beam. The safety clamp can beconfigured to prevent the piston rod from disengaging from the housingin response to rocking of the walking beam.

FIG. 1 shows one embodiment of an oil well pump P having a compressor Cmounted thereon. As shown, the oil well pump P generally includes awalking beam 10 pivotally mounted to a top of a Samson post 12 by abearing 11. A horsehead 14 on one end of the walking beam 10 can beconnected to a rod 16 for operating a downhole pumping system as is wellunderstood in the oil production industry. A connecting rod 18 can beconnected through a linkage 20 to a gear box 22 which drives the pump P.The compressor C can have a lower cover plate 34 with a lower supportleg 32 coupled thereto and extending therebetween. A bottom portion ofthe support leg 32 can be pivotally connected to a bracket 38 attachedto a leg of the Samson post 12 by a clamp 40. Additional clamps 42 canbe provided at each end of clamp 40, as shown, to minimize possiblemovement of the clamp 40 along the leg of Samson post 12 during thepumping operation. It will be appreciated by those skilled in the artthat the lower cover plate 34, and hence the bottom portion of thecompressor, can be coupled to any stationary portion of the oil wellpump P as needed. For example, the lower cover plate 34 can also beattached to a base 44, if desired. The compressor C can have a pistonrod 24 attached at its upper end to a securing mechanism 100 and thatterminates at its lower end within the compressor C. The securingmechanism 100 can generally be effective to couple the piston rod 24 tothe walking beam 10 in such a manner that prevents the piston rod 24from disengaging from the walking beam 10 during operation of the oilwell pump P. Exemplary oil well pumps and compressors are described inmore detail in U.S. Pat. No. 6,572,116 of Turiansky, U.S. Pat. No.6,164,935 of Turiansky, and U.S. Pat. No. 6,305,918 of Turiansky,incorporated herein by reference in their entireties.

While many securing mechanisms are possible for coupling the walkingbeam compressor C to the walking beam 10, FIG. 2 illustrates oneembodiment of the securing mechanism 100. The securing mechanism 100generally provides a mechanism to ensure that the piston rod 24, andthereby the compressor C, remains coupled to the walking beam 10. In theillustrated embodiment, the securing mechanism 100 generally includes ahousing 26 for mating with a proximal portion of the piston rod 24. Thehousing 26 can be coupled via a retaining rod 102 and a bearing 104 to awalking beam plate 106, which is fastened to the walking beam 10. Asafety clamp 200 can be attached between the piston rod 24 and thehousing 26, as shown in FIG. 3, to ensure that the piston rod 24 doesnot come uncoupled from the housing 26.

The housing 26 can have various configurations but is preferablyeffective to receive an upper or proximal end of the piston rod 24 tojoin the piston rod 24, and thereby the compressor C which is disposedaround a lower distal end of the piston rod 24, to the walking beam 10.A person skilled in the art will appreciate that there are manyvariations of housings for joining a piston rod 24 to a walking beam 10,however, in the illustrated embodiment the housing 26 is in the form ofa clevis eye having the shape of a generally rectangular box. As shownin FIGS. 2 and 3, the housing 26 can have a top sidewall 110 and abottom sidewall 112, as well as a front sidewall 120 generally facing ina direction towards the horsehead 14 of the oil well and an opposed backsidewall 122. A bore 108 can be formed through left and right sidewalls103, 105 of the housing 26 in a configuration parallel to the top andbottom sidewalls 110, 112 for receiving the retaining rod 102. The bore108 can be formed at a position on the left and right sidewalls 103, 105that is centered between the front and back sidewalls 120, 122. The bore108 can also be centered between the top and bottom sidewalls 110, 112,but in an exemplary embodiment as shown, it can be positioned closer tothe top sidewall 110.

While various techniques can be used for coupling the housing 26 to thewalking beam 10, in an embodiment the housing 26 can be coupled to thewalking beam 10 by a beam plate 106 having two beam plate brackets 28extending in a downward direction substantially perpendicular to thebeam plate 106. The beam plate 106 can have a top surface 116 forfixedly mating to an upper beam plate 30, shown in FIG. 1. The beamplates 106, 30 together engage the walking beam 10. The beam plate 106can further include a bottom surface 118 from which the beam platebrackets 28 can extend. The beam plate brackets 28 can be integrallyformed with the beam plate 106 such that the brackets 28 and the beamplate 106 are formed from a single piece of material, such as, forexample, steel and/or titanium. Alternatively, the beam plate brackets28 can be coupled to the beam plate 106 by any fastening mechanism knownin the art, including but not limited to retaining rods, bolts,adhesive, etc.

While there are many configurations possible for the beam plate brackets28, in one embodiment the beam plate brackets 28 can be spaced adistance d apart that is slightly larger than a width w of the housing26 such that the beam plate brackets 28 can be positioned adjacent tothe left and right sidewalls 103, 105 of the housing 26 with the topsidewall 110 of the housing 26 being in proximity to the bottom surface118 of the beam plate 106. The beam plate brackets 28 can each have abore 124 formed therethrough that can be aligned with the bore 108formed in the housing 26. The retaining rod 102 can extend through thebore 108 in the housing 26 and through the bores 124 in the beam platebrackets 28 positioned on each side of the housing 26. A rotary bearing104 can optionally be positioned within the bores 124 in the beam platebrackets 28 to connect the retaining rod 102 between the housing 26 andthe beam plate brackets 28, thereby allowing the beam plate 106 and thebeam plate brackets 28 to rotate with respect to the housing 26 inresponse to the reciprocating motion of the walking beam 10.

The beam plate 106 can be mated with the upper beam plate 30 using avariety of fastening mechanisms known in the art. In one embodiment, asshown in FIG. 2, the beam plate 106 can include a plurality of fasteningholes 126, such as bolt holes, for receiving fastening members, such asbolts, for mating with the upper beam plate 30 and thus the walking beam10. In particular, in one embodiment, fastening members can extendthrough the fastening holes 126 in the beam plate 106 to extend throughcorresponding holes in the walking beam 10 and into receiving holes inthe upper beam plate 30. A person skilled in the art will appreciatethat any fastening mechanism known in the art can be used to fasten thebeam plate 106 with the walking beam 10. In this way, the beam plate 106and beam plate brackets 28 can be rigidly attached to the walking beam10. In effect, because the walking beam 10 reciprocates in an arcuateconfiguration with respect to a flat surface, such as the ground, therigidly attached beam plate 106 and beam plate brackets 28 have acorresponding arcuate motion. Thus, the retaining rod 102 and the rotarybearings 104 allow the beam plate 106 and beam plate brackets 28 torotate with respect to the housing 26, thereby effectively convertingthe arcuate motion of the walking beam 10 and the beam plate 106 intovertical longitudinal motion. In this way, the housing 26 can beconfigured to move in a vertical or longitudinal direction. Thisvertical motion in the housing 26 is transferred to the piston rod 24 toeffect intake and compression strokes within the walking beam compressorC.

The piston rod 24 can be mated to the housing 26 by any securingmechanism known in the art effective to rigidly attach the piston rod 24to the housing 26. In the exemplary embodiment shown in FIG. 2, thebottom sidewall 112 of the housing 26 includes a circular bore 128formed therein having threads formed around an interior surface 130thereof for receiving a threaded terminal or proximal end 132 of thepiston rod 24. Thus, the piston rod 24 can be threadably mated to thehousing 26 to receive the vertical reciprocal motion that has been“converted” from the arcuate motion of the walking beam 10. A distalportion of the piston rod 24 can extend into the walking beam compressorC to effect intake and compression strokes therein to receive andcompress gas. It is the reciprocal motion associated with the piston rod24, however, that can cause the threaded proximal end 132 of the pistonrod 24 to gradually back out of or become unthreaded from the threadedbore 128 in the housing 26. Over time, as the piston rod 24 slowlyunscrews from the bore 128 in the housing 26, the effective length ofthe piston rod 24 increases. The increased length of the piston rod 24increases the length of the compression strokes within the compressor C.Increased compression strokes can cause a distal end of the piston rod24 to “bottom out” in the compressor C causing damage to both thecompressor C and to the piston rod 24. Further, if the threaded proximalend 132 of the piston rod 24 backs out far enough, it will eventuallybecome completely disengaged from the housing 26 and can cause thecompressor C to fall away from the walking beam 10. Thus, the safetyclamp 200 is provided to prevent rotation of the piston rod 24 relativeto the housing 26.

The exemplary embodiment of the safety clamp 200 is illustrated in moredetail in FIGS. 4A-4D, although some aspects of the safety clamp 200 canalso be seen in FIGS. 2 and 3. As shown in FIGS. 4A-4D, the safety clamp200 can include first and second clamping legs 202 a, 202 b mated toopposed sides of a central extension 204 such that the first and secondclamping legs 202 a, 202 b are spaced apart from one another and extendin a generally parallel configuration to each other and in a directionthat is perpendicular to the central extension member 204. The first andsecond clamping legs 202 a, 202 b can have a variety of shapes andconfigurations, but in the illustrated embodiment the clamping legs 202a, 202 b have a generally elongate rectangular shape. The first andsecond clamping legs 202 a, 202 b can have exterior surfaces 206 a, 206b that face away from each other and interior surfaces 208 a, 208 b thatface towards each other. The first and second clamping legs 202 a, 202 bcan also have first ends 210 a, 210 b and second ends 212 a, 212 b. Thecentral extension member 204 can also have a variety of shapes andconfigurations, but in the illustrated embodiment, the central extensionmember 204 has a generally elongate rectangular shape with an interiorsurface 214 that faces in the direction of the clamping legs 202 a, 202b and an exterior surface 216 that faces in a direction away from theclamping legs 202 a, 202 b. The central extension member 204 can mate tothe interior surfaces 208 a, 208 b of the first and second clamping legs202 a, 202 b at or adjacent to the first ends 210 a, 210 b such that thecentral extension member 204 and the first and second clamping legs 202a, 202 b form a substantially L-shaped clamp.

The safety clamp 200 can be formed of any material known in the arthaving the required strength properties, including but not limited tosteel and/or titanium. Thus, any mating technique known in the art formating such materials can be used to mate the central extension member204 with the first and second clamping legs 202 a, 202 b. For example,the central extension member 204 and the first and second clamping legs202 a, 202 b can be welded, extruded, or integrally formed from a singlepiece of material. Alternatively, they can be mated with fasteningmembers such as bolts or retaining rods, or they can be glued. A personskilled in the art will appreciate the many alternatives for mating thecentral extension member 204 with the clamping legs 202 a, 202 b.

While there are many ways to secure the safety clamp 200 to the pistonrod 24, in one exemplary embodiment the safety clamp 200 can include aretaining element 220 for securing the first and second clamping legs202 a, 202 b around the piston rod 24, as will be described in moredetail below. The retaining element 220 can have a generally cylindricalshape and can extend between interior surfaces 208 a, 208 b of thesecond ends 212 a, 212 b of the first and second clamping legs 202 a,202 b. The retaining member 220 can be hollow and can therefore receivea fastening member 222, such as a threaded bolt, therethrough. Inparticular, the first and second clamping legs 202 a, 202 b can includebores 224 a, 224 b formed through the second ends 212 a, 212 b, as shownin FIG. 3. In this way, the fastening member 222 can be inserted throughthe bore 224 b in the second clamping leg 202 b to extend through theretaining element 220 and through the bore 224 a in the first clampingleg 202 a. A threaded securing element, such as a nut 226 and a washer228, can engage the fastening member 222 thereby securing the retainingelement 220 between the first and second clamping legs 202 a, 202 b. Aswill be appreciated by those skilled in the art, the fastening member222 can also be initially inserted through the first clamping leg 202 ato extend through the retaining member 220 and the second clamping leg202 b and thereby be secured. A person skilled in the art will furtherappreciate that any fastening mechanism known in the art can be used tosecure the clamping legs together and/or to secure the retaining elementbetween the first and second clamping legs.

In one embodiment, the safety clamp 200 can mate to both the piston rod24 and the housing 26. As shown in FIG. 2, the piston rod 24 can haveopposed cut-outs, notches, or recesses 230 formed in a proximal portionthereof, preferably at a location just below where the piston rod 24mates to the housing 26. The recesses 230 can have a shape and size thatwill snuggly seat the first and second clamping legs 202 a, 202 btherein. In particular, as best shown in FIG. 3, the opposed recesses230 in the piston rod 24 each have a generally rectangular shape suchthat they are configured to seat middle portions of the first and secondclamping legs 202 a, 202 b. As a result, the central extension member204 will be positioned on one side of the piston rod 24 and theretaining member 220 will extend between the first and second clampinglegs 202 a, 202 b on a side of the piston rod 24 opposed to the centralextension member 24. In general, as will be appreciated by those skilledin the art, the first and second clamping legs 202 a, 202 b can besimply seated within the recesses 230 by way of a press fit, without anyneed for a fastening or securing mechanism. In other exemplaryembodiments, the first and second clamping legs 202 a, 202 b can be, forexample, fastened, glued, or otherwise fixedly attached to or integrallyformed with the recesses 230 in the piston rod 24. The central extensionmember 204 can extend in a direction parallel to the piston rod 24 andperpendicular to the first and second clamping members 202 a, 202 b tomate with the housing 26 situated above the opposed recesses 230 in thepiston rod 24. In one embodiment, the central extension member 204 canbe positioned such that its interior surface 214 is positioned adjacentto the back portion 122 of the housing 26, as is most clearly shown inFIG. 3. The central extension member 204 can be rigidly mated to thehousing 26 using any method known in the art, including but not limitedto a fastening member, press fit, adhesive, etc. A person skilled in theart will appreciate, however, that the central extension member 204 canextend from any portion of the clamping legs 202 a, 202 b and can extendinto and/or mate to any portion of the housing 26.

In use, because the safety clamp 200 is a generally rigid member thatwill rigidly engage the piston rod 24 and the housing 26, the safetyclamp 200 will prevent rotation between the piston rod 24 and thehousing 26. In particular, since the first and second clamping legs 202a, 202 b are rigidly mated to the central extension member 204, thefirst and second clamping legs 202 a, 202 b effectively “grip” thepiston rod 24 and correspondingly do not allow the piston rod 24 torotate. The retaining member 220 can secure the first and secondclamping legs 202 a, 202 b together to prevent the first and secondclamping legs 202 a, 202 b from expanding if the piston rod 24 attemptsto rotate. Thus, the piston rod 24 is held securely in place and cannotback out or rotate out of the threaded bore 128 in the housing 26 inresponse to the rocking of the walking beam. A person skilled in the artwill appreciate that there are many other configurations possible forthe safety clamp 200, and the embodiments disclosed herein are notintended to limit the use of the safety clamp 200 to the particularembodiments illustrated. Any configuration in which the safety clamp ismated to the walking beam or other portion of the oil well in such a wayas to prevent the piston rod from rotating with respect to the housingis to be included in the embodiments and invention described herein.

Methods of securing a piston rod to a walking beam on an oil well pumpare also provided. In one exemplary embodiment, a piston rod can have awalking beam compressor disposed around a distal end thereof. A proximalportion of the piston rod can be threaded into a bore within a housingthat is coupled to the walking beam of an oil well. Generally, a safetyclamp can be coupled between the housing and the piston rod to securethe two together and to prevent the piston rod from unthreading from thebore in the housing. In an exemplary embodiment, first and secondclamping legs can be positioned within opposed recesses formed in thepiston rod, preferably at a distance below where the piston rod threadsinto the housing. The central extension member can be secured to thehousing, for example, by a fastening member such as a bolt, an adhesive,or a press fit. The clamping legs can be secured around the piston rod,and while there are many ways to do so, in one embodiment, a hollow,cylindrical retaining element can be positioned between the first andsecond clamping legs. A fastening member, such as a bolt, can beinserted through a bore formed in the first clamping leg, through acenter of the retaining member, and into a bore formed in the secondclamping leg. A nut and washer system or other fastening mechanism canbe tightened to the threaded end of the bolt to secure the two clampinglegs together with the retaining member therebetween. Thus, a rigidcenter extension member is coupled to a rigid housing that cannotrotate. First and second rigid clamping legs are mated to the centralextension member and seated within recesses formed in the piston rod. Inthis way, because the central extension member cannot rotate, the firstand second clamping legs are prevented from rotating. In the same way,the first and second clamping legs prevent the piston rod from rotating.This exemplary method of assembly prevents the piston rod fromunthreading or unscrewing from the housing during the reciprocal motionproduced by the walking beam.

A person skilled in the art will appreciate that, while the exemplarymethod is described in connection with the particular embodimentsdisclosed herein, the method can vary significantly depending on theparticular configuration of the securing mechanism, as well as theconfiguration of the walking beam compressor.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

1. An oil well pump, comprising: a walking beam for pumping oil out of the ground; a housing mated to the walking beam and having a piston rod extending therefrom; and a safety clamp coupled to the housing and the piston rod and configured to prevent the piston rod from rotating relative to the housing, wherein the safety clamp includes first and second legs that engage opposing recesses in the piston rod, and wherein the safety clamp includes a retaining element extending between the first and second clamping legs and configured to secure the clamping legs to the piston rod.
 2. The oil well pump of claim 1, wherein the piston rod is threadably mated to the housing.
 3. The oil well pump of claim 1, wherein the safety clamp further includes a central arm extending from between the first and second legs and coupled to the housing.
 4. The oil well pump of claim 2, wherein the housing includes a threaded bore configured to threadably receive a threaded terminal end of the piston rod.
 5. The oil well pump of claim 1, wherein the housing comprises a clevis eye.
 6. The oil well pump of claim 1, wherein the walking beam includes a beam plate coupled thereto, and wherein the housing is rotatably mated to a bracket extending from the beam plate.
 7. The oil well pump of claim 1, wherein the piston rod is configured for reciprocal longitudinal movement in response to rocking movement of the walking beam.
 8. The oil well pump of claim 1, wherein the safety clamp is substantially L-shaped.
 9. An oil well pump, comprising: a walking beam for pumping oil out of the ground; a housing rotatably coupled to the walking beam and having a threaded bore formed therein; a piston rod having a first threaded terminal end threadably mated to the threaded bore in the housing and a second terminal end extending into a compressor configured to receive and compress gas contained with oil pumped out of the ground; and a safety clamp coupled to the housing and the piston rod and configured to prevent the piston rod from unthreading from the housing, wherein the safety clamp includes first and second clamping legs positioned in opposing recesses in the piston rod, and wherein the safety clamp includes a retaining element extending between the first and second clamping legs and configured to secure the clamping legs to the piston rod.
 10. The oil well pump of claim 9, wherein the safety clamp includes a central arm extending from between the first and second clamping legs and coupled to the housing, the clamping legs and central arm configured to prevent the piston rod from rotating.
 11. The oil well pump of claim 10, wherein the central arm extends substantially perpendicular to the first and second clamping legs to form a substantially L-shaped safety clamp.
 12. The oil well pump of claim 9, wherein the housing comprises a clevis eye.
 13. A method of securing a piston rod to a walking beam on an oil well pump, comprising: threading a piston rod into a housing coupled to a walking beam for pumping oil out of the ground; coupling a safety clamp to the housing and the piston rod to prevent the piston rod from unthreading from the housing, wherein coupling the safety clamp to the piston rod comprises positioning first and second clamping legs of the safety clamp within opposing recesses formed in the piston rod; and bolting a retaining element to the first and second clamping legs to prevent removal of the first and second clamping legs from the piston rod.
 14. The method of claim 13, wherein coupling the safety clamp to the housing comprises bolting a central arm of the safety clamp to the housing. 